Bacterial aminopeptidases: Properties and functions

Abstract

Aminopeptidases are exopeptidases that selectively release N-terminal amino acid residues from polypeptides and proteins. Bacteria display several aminopeptidasic activities which may be localised in the cytoplasm, on membranes, associated with the cell envelope or secreted into the extracellular media. Studies on the bacterial aminopeptide system have been carried out over the past three decades and are significant in fundamental and biotechnological domains. At present, about one hundred bacterial aminopeptidases have been purified and biochemically studied. About forty genes encoding aminopeptidases have also been cloned and characterised. Recently, the three-dimensional structure of two aminopeptidases, the methionine aminopeptidase from Escherichia coli and the leucine aminopeptidase from Aeromonas proteolytica, have been elucidated by crystallographic studies. Most of the quoted studies demonstrate that bacterial aminopeptidases generally show Michaelis-Menten kinetics and can be placed into either of two categories based on their substrate specificity: broad or narrow. These enzymes can also be classified by another criterium based on their catalytic mechanism: metallo-, cysteine- and serine-aminopeptidases, the former type being predominant in bacteria. Aminopeptidases play a role in several important physiological processes. It is noteworthy that some of them take part in the catabolism of exogenously supplied peptides and are necessary for the final steps of protein turnover. In addition, they are involved in some specific functions, such as the cleavage of N-terminal methionine from newly synthesised peptide chains (methionine aminopeptidases), the stabilisation of multicopy ColE1 based plasmids (aminopeptidase A) and the pyroglutamyl aminopeptidase (Pcp) present in many bacteria and responsible for the cleavage of the N-terminal pyroglutamate.

Cloning and functional expression of dipeptidyl peptidase IV from the ruminal bacterium Prevotella albensis M384T

“…albensis is similar to the majority of peptidase genes, which do not exist as an operon, are monocistronic and are generally transcribed from a s 70 promoter (Gonzales & Robert-Baudouy, 1996). Putative promoter regions were identified within the upstream region of dpp-IV (CAGAT and TATCTTTG), similar to those previously identified in Por.…”

A Secreted Aminopeptidase of Pseudomonas aeruginosa

“…Both belong to the same family (M28) of Zn-dependent proteolytic enzymes with co-catalytic metal centers (23). Unlike most intracellular aminopeptidases which form oligomeric structures (20,24), VpAP * This work was supported in part by Grant G800 from the Cystic Fibrosis Foundation (to E. K.), by Public Health Service Grant AI 26187 from NIAID, National Institutes of Health (to D. E. O.…”

Function of the N-terminal propeptide of an aminopeptidase from Vibrio proteolyticus

“…Approx. 100 bacterial aminopeptidases have been purified and biochemically studied, and nearly 40 genes encoding aminopeptidases have been cloned and characterized [1].…”

“…Cloning and sequencing of the gene encoding the apVP indicates that it is translated as a preproprotein consisting of four domains : a signal peptide (21 amino acid residues), an NAbbreviations used : apAC, aminopeptidase from Aeromonas caviae T-64 ; apVP, aminopeptidase from Vibrio proteolyticus ; PA protease, proaminopeptidase-processing protease from Aeromonas caviae T-64. 1 To whom correspondence should be addressed (e-mail khayashi!nfri.affrc.go.jp).…”